Remotely resettable fire damper

ABSTRACT

A folding blade type fire damper is provided with a thermally actuated resettable release link and retraction means cooperating with the link to reset the blades in their retracted condition upon actuation from outside the duct in which the damper is mounted.

United States Patent 1191 McCabe 1 Mar. 12, 1974 [5 REMOTELY RESETTABLEFIRE DAMPER 2,148,530 2/1939 Burke 126/2875 ux 3,665,996 5/1972Roberts.. 160/1 [76] Invent Franc f 3,687,185 8/1972 Singer 160/1 Box181, Buckmgham, Pa. 18912 [22] Filed: Aug. 28, 1972 PrimaryExaminerMervin Stein [211 App! 28422l Assistant Examiner-Philip C.Kannan Related US. Application Data [63] Continuation-impart of Ser. No.178,111, Sept. 7,

1971, Pat. No. 3,725,972. 7

[57] ABSTRACT [52] US. Cl 160/1, 160/35, 160/84 [51] Int. Cl E05f 15/20A folding blade type fire damper is provided with a [58] Field of Search160/1, 84, 5, 6, 36, 35; thermally actuated resettable release link andretracl26/287.5, 285; 137/457, 79; 98/85, 86; tion means co-operatingwith the linkto reset the 1 251/66, 68 blades in their retractedcondition upon actuation from outside the duct in which the damper is[56] References Cited mounted.

UNITED STATES PATENTS 3,646,877 3/1972 Ellis 160/84 X -12 Claims, 5Drawing Figures CROSS REFERENCE TO APPLICATION DESCRIPTION OF THEPREFERRED EMBODIMENTS Although specific forms of the invention have beenThis application is a continuation-in-part of my prior selected forillustration in the drawings, and the followco-pending application for aFire Link and Method of Actuating Same Ser. No. 178,] l l, filed Sept.7, 1971, now US. Pat. Nos 3,725,972, and discloses and claims, in part,the subject matter disclosed and claimed therein.

BACKGROUND OF THE INVENTION This invention relates to thermally actuatedfire dampers used in air ducts, and more particularly to a resettablelink and a means co-operating therewith to reset the fire damper in itsfolded condition, from without the duct.

In the proir art, folding blade fire dampers such as those shown in myUS. Pat. No. 3,273,632 and 3,401,734 were retained in a folded orretracted condition by a wire or chain held by a fusable link. The linkwas not resettable.

In my prior co-pending application I disclose a resettable link whichcan be actuated by a remote electrical signal to release the damper fromits folded condition and allow it to extend to its fire blockingunfolded condition in the air duct in which it is mounted. However, inorder to reset the damper in its retracted condition it is necessary togain access to the air duct. It is desirable to be able to reset thedamper remotely from outside the air duct. I

SUMMARY OF THE INVENTION associated with it for improved response tothermal conditions in theduct.

Accordingly, it is an object of my invention to improve'fire dampersystems by providing a means for remotely opening and resetting dampersmounted in ducts.

This and other objects of my invention will become apparent from thefollowing description of the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevation of a remotelyresettable folding blade fire damper in accordance with my inventionshown partially in section, mounted in its environmental condition withalternate positions shown in phantom lines;

FIG. 2 is a partial plan view taken as indicated by the lines and arrows2--2 in FIG. 1;

FIGv 3 is a section on a greatly enlarged scale taken as indicated bythe lines and arrows 33 in FIG. 2;

FIG. 4 is a partial view similar to FIG. 3 showing the parts in analternate position; and

FIG. 5 is a plan view taken as indicated by the lines and arrows 5-5 inFIG. 3.

ing description is drawn in specific terms for the purpose of describingthere forms of the invention, this description is not intended to limitthe scope of the invention which is defined in the appended claims.

A folding blade fire damper of the type disclosed in my patentsreferenced above is shown in FIG. 1 designated generally 10 in itsenvironmental condition mounted in an air duct shown in phantom linesand designated generally 12. The damper comprises a frame 14 and aplurality of blades shown schematically and designated generally 16. Theblades shown in full lines are in their folded or retracted condition.This is the condition in which they would normally be retained by a wireor chain and fusable link. In the prior art, when the link melted andseparated, the blades unfolded and extended to the bottom of the frameas shown by the phantom lines at A. This wasthe unfolded or.fullyextended condition in which they prevented air and fire from passingthrough the duct.

If it was desired to reset the damper, then it was necessary to gainaccess to the duct. One had to reach into the duct and raise the bladesby hand to their folded condition B and then attach'another fusablelink. By using a resettable link, the same link can be used again. Byusing the present invention, the damper can be reset from outside theduct. Among the advantages of this invention is that it provides a meansfor testing the functioning of the damper periodically at greatlyreduced maintenance and test costs.

The damper reset comprises a pivotally mounted angled arm 18. The armisv made of flat metal, preferably several inches wide to provide astable surface upon which to rest the blades and to raise the bladeswithout.

cocking them. This is accomplished as shown in phantom lines in FIG. 1depicting several alternate positions. With the blades extended as at Aa flexable braided wire 20 is loosely positioned as at C underneath thefree end of the last blade. One end of the wire 20 passes through a holein the free end of the arm 18 and is retained from being pulled throughthe hole by a metallic clip 22. The wire 20 passes over a pulley 24which is fixedly attached to the upper extension 26 of the frame 10; theextension 26 being cantilevered from the top of the frame. The other endof the wire 20 extends through a hole 28 in the bottom of the frame 10and a hole 30 in the duct, and terminates in a handle 32 attachedthereto in any suitable manner.

The arm 18 is pivoted about a pin 36. Accordingly,

when the handle 32 is pulled from outside the duct, the wire 20 is drawnover the pulley 24 and begins to lift the blades 16. As more and morewire is withdrawn the blades are folded and raised upwardly and the arm18 begins to engage the blades as shown at D. Upon further retraction,the arm fully pivots to the position shown in full lines wherein the end38 FIG. 3 of the arm 18 mechanically interlocks with the pin 40 of theresettable link designated generally 42.

The link comprises a base 44 upon which are mounted a plurality of metalstrips each insulated from the other and from the base. The outer strip46 is a bimetallic thermally responsive element which when heated movesin the direction of the arrow E FIG. 4.

The rivet 48 retains the fixed end of the element 46 be- 52 slightlynarrower than the end 58"(on the order of 0.030of an inch less) as thiswill direct the bending slightly forward to advantageously release thepin 40 from the hole-60. The pin 40 is cocked at its free end slightlyback in a direction toward the rivet 48 in order to hold greater weightwhen engaged by the arm 38 as in FIG. 3. Accordingly, causing thegreatest bending to occur closer to the free end of the element 46 uponheating of the element, provides for the release of more weight moreefficiently.

The element 62 is a thin, flat strip of metal fixedly held at one end bythe rivet 48 between the insulator spacers 64 and 50. The metal member62 is preformed or bent so that its normal positionQwhen not acted uponby the member 46 would be that shown in part in FIG. 4. However, themember 46 is a heaviergauge material and in its normal-unheatedcondition it assumes the position shown in FIG. 3 wherein it forces thefree end of element 62 back toward the base 44. The element 62 hassufficient spring resiliency in it so that it is not deformed by thisaction and will move to its normal position as shown in FIG. 4 when theelement 46 has been sufficiently heated to bendit in the direction ofthe arrow E to the position shown in FIG. 4.

An electrical contact 63 is provided on the end of element 62 to engagean electrical contact '47 on element 46 and and complete the electricalcircuit necessary to remotely heat element 46. When these contacts areseparated as in FIG. 4 the circuit is broken and heating ceases.Thereafter, as element46 cools, itbegins to return to its normalcondition as shown in FIG. 3. As long as the electrical signalis presentwhen the contacts 43 and 47 again engage, the element 46 will againbegin to heat up. The purpose of this is to .prevent overheating of thebimetallic element 46, which could cause 4 force of the member 46. Itshould be noted that the pin .40 is fixedly held on the end of themember 46, and is electrically insulated therefrom by the insulators 76.

To aid in guiding the pin into the hole60, the hole is made slightly oversized and the tabs 78 FIGS. 2 and 5 extending from the endof the end38 are positioned closely adjacent to the walls 84 of the shroud 72.This provides an initial guide for the pin. In addition, the end 86 ofthe arm end 38 fits closely within the walls of the shroud therebyproviding a further guide.

It will be apparent from what has been disclosed that various changesmay be made by those skilled in the art within the principle and'scopeof the invention. For example, the cable 20 could be remotelycontrolled.

It should be noted that when the cable is retracted in the duct, itprovides a visible indicator outside the duct that the damper bladeshave fallen.

It will further be understood that the Abstract of the Disclosure setforth above is intended to provide a non-legal technical statement ofthe contents of the disclosure in compliance with the Rules of Practiceof the United States Patent Office, and is not intended to limit thescope of the invention described and claimed herein.

What is claimed is:

1. In combination with a folding blade damper having I blades movablebetween a folded and unfolded condition, the improvement comprising: aresettable link thermally actuatable between a closed and openedcondition, comprising a bimetallic element cantilevered from a supportconnected to said damper and having a narrow neck portion intermediatethe free end and the supported end, which element is thermallyresponsive to open and close said link; and a retraction means connectedto said damper cooperating with said link to move said blades from theirunfolded to their folded condition and retain them in their foldedcondition upon actuation from outside said damper.

2. The invention of claim 1 wherein said link has a pin extending fromthe free end of said element toward elastic deformation or burning up ofthe electric circuit components.

The base 44 is fixedly attached as by. riveting to an agnled bracket 70which is fixedly attached by any suitable means to the overhang 26. Theangled bracket is a solid piece of metal. Mounted about the bracket andlink 42 is a solid metallic shroud 72. The shroud can be fixedly orpivotally attached to the angled bracket 70.

As shown, it provides an enclosure about the link 42 open only at thelower end designated generally 74 FIG. 3. This prevents heat dissipationwhich would result from air flowing through the duct attoo fast a rate.The open end would allow entry of hot air for thermal actuation; whilepreventing air flow through.

To aid in the mechanical interlocking of the end 38 with the pin 40, lhave provided a sloping surface 80 on the pin 40 which is engaged by thesloping surface 82 of the advancing end 38 of the arm. As the wire 20 isdrawn through the device the advancing end 38 cams the pin 40 outwardlyfrom its normal position in FIG. 3 until the hole 60 is aligned with thepin 40 and the. pin

drops into place as shown in FIG. 3 under the springsaid support forengaging said retraction means.

3. The invention of claim 2 wherein said neck is narrower at the endthereof most remote from'saidsupport.

4. In combination with a folding blade damper having blades movablebetween a folded and unfolded condition, the improvement comprising: aresettable link connected to said damper; and a retraction means com-.prising an arm pivotally connected to said damper; said arm adapted tomechanically interlock with said link when said blades are in a foldedcondition and retain them in their folded condition; and a flexiblemember connected to the free end of said arm and coacting with saiddamper to pivot said arm and fold said blades upon retraction fromoutside saiddamper.

5. The invention of claim 4 wherein in the unfolded condition said armis disposed on one side of said blades and said flexible member passesabout the free end of one of said blades.

6. The invention of claim 4 wherein said damper has a frame'and saidflexible member extends beyond said frame in both the folded andunfolded condition.

7.-The invention of claim 2 wherein said link comprises a bimetallicelement having a pin extending from one end presenting a beveled surfaceto the free end of said arm.

8. The invention of claim 4.wherein said arm has a guide means at itsfree end to guide it into engagement with said link.

9. In combination with a folding blade damper having blades movablebetween a folded and unfolded condition, the improvement comprising: aresettable link connected to said damper; and a retraction meansconnected to said damper cooperating with said link to move said bladesfrom their unfolded to their folded condition and retain them in theirfolded condition upon actuation from outside said damper; said linkcomprising a bimetallic element cantilevered from a support thermallyactuatable between a closed and opened condition of engagement anddisengagement with said retraction means; and a second elementcantilevered from said support; said elements being electricallyinsulated from each other and from said support; said elementscomprising an electric switch.

10. The invention of claim 9 wherein said second element is resilientand is movable between a flexed position in engagement with saidbimetallic element and an upon actuation from outside said damper; saidresettable link comprising a bimetallic element cantilevered from asupport and having engagement means at the free end thereof for engagingsaid retraction means; said bimetallic element being thermallyactuatable between a closed and opened condition of engagement anddisengagement with said retraction means and being substantially closedby a shroud.

1. In combination with a folding blade damper having blades movablebetween a folded and unfolded condition, the improvement comprising: aresettable link thermally actuatable between a closed and openedcondition, comprising a bimetallic element cantilevered from a supportconnected to said damper and having a narrow neck portion intermediatethe free end and the supported end, which element is thermallyresponsive to open and close said link; and a retraction means connectedto said damper cooperating with said link to move said blades from theirunfolded to their folded condition and retain them in their foldedcondition upon actuation from outside said damper.
 2. The invention ofclaim 1 wherein said link has a pin extending from the free end of saidelement toward said support for engaging said retraction means.
 3. Theinvention of claim 2 wherein said neck is narrower at the end thereofmost remote from said support.
 4. In combination with a folding bladedamper having blades movable between a folded and unfolded condition,the improvement comprising: a resettable link connected to said damper;and a retraction means comprising an arm pivotally connected to saiddamper; said arm adapted to mechanically interlock with said link whensaid blades are in a folded condition and retain them in their foldedcondition; and a flexible member connected to the free end of said armand coacting with said damper to pivot said arm and fold said bladesupon retraction from outside said damper.
 5. The invention of claim 4wherein in the unfolded condition said arm is disposed on one side ofsaid blades and said flexible member passes about the free end of one ofsaid blades.
 6. The invention of claim 4 wherein said damper has a frameand said flexible member extends beyond said frame in both the foldedand unfolded condition.
 7. The invention of claim 2 wherein said linkcomprises a bimetallic element having a pin extending from one endpresenting a beveled surface to the free end of said arm.
 8. Theinvention of claim 4 wherein said arm has a guide means at its free endto guide it into engagement with said link.
 9. In combination with afolding blade damper having blades movable between a folded and unfoldedcondition, the improvement comprising: a resettable link connected tosaid damper; and a retraction means connected to said damper cooperatingwith said link to move said blades from their unfolded to their foldedcondition and retain them in their folded condition upon actuation fromoutside said damper; said link comprising a bimetallic elementcantilevered from a support thermally actuatable between a closed andopened condition of engagement and disengagement with said retractionmeans; and a second element cantilevered from said support; saidelements being electrically insulated from each other and from saidsupport; said elements comprising an electric switch.
 10. The inventionof claim 9 wherein said second element is resilient and is movablebetween a flexed position in engagement with said bimetallic element andan unflexed position when no longer engaging said bimetallic element.11. The invention of claim 9 wherein said switch remains closed whilesaid link engages said retraction means.
 12. In combination with afolding blade damper having blades movable between a folded and unfoldedcondition, the improvement comprising: a resettable link connected tosaid damper; and a retraction means connected to said damper cooperatingwith said link to move said blades from their unfolded to their foldedcondition and retain them in their folded condition upon actuation fromoutside said damper; said resettable link comprising a bimetallicelement cantilevered from a support and having engagement means at thefree end thereof for engaging said retraction means; said bimetallicelement being thermally actuatable between a closed and opened conditionof engagement and disengagement with said retraction means and beingsubstantially closed by a shroud.